Method of operating an energy recovery system

ABSTRACT

A method of operating an energy recovery system includes providing a flow of fresh air from an energy recovery ventilator through a supply port into a component of a heating and cooling system. Stale air is blown from the component through a return port into the energy recovery ventilator, the return port including a shield configured to at least partially prevent fresh air flowing from the supply port into the component from recirculating through the return port.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/074,055 filed Nov. 7, 2013, which claims the benefit of anearlier filing date of U.S. Patent Application No. 61/749,658, filedJan. 7, 2013 the contents of which are incorporated by reference hereinin their entirety.

BACKGROUND OF THE INVENTION

Embodiments relate generally to heat and mass exchangers and, moreparticularly, to an energy recovery ventilator (“ERV”) that attachesdirectly to an existing furnace, fan coil or air handler and uses twoduct connections for recovering energy from indoor air.

An ERV is generally used with a heating and cooling system to exhauststale air from a stale air space to a fresh air space and bring in freshair from the fresh air space to the stale air space while exchangingheat or cool energy, thereby reducing heating or cooling requirements.Typically, an ERV includes a heat and mass exchanger contained in ahousing for exchanging heat or cool energy. The exchanger may berotating or stationary. When the ERV is used with a heating and cooling,an outside air stream ducted from the outdoors and a stale room airstream from the return air duct or furnace, fan coil, or air handlerseparately enter the ERV and pass through the heat and mass exchanger.Within the heat and mass exchanger, energy from the stale room airstream is transferred either to or from the outside air stream. Theoutside air stream then exits the ERV to the supply air duct or furnace,fan coil, or air handler as a fresh air stream. The stale room airstream then exits the ERV to the outdoors through a duct as an exhaustroom air stream.

Most residential ERVs are mounted on a wall or ceiling and generallyrequire four duct pipes to exchange cool or heat energy with an airhandler system. In an example, the outside air stream and the stale roomair stream enter the housing through duct pipes connected to two airflow openings in the housing. The fresh air stream and the exhaust roomair stream exit the housing through two other duct pipes connected totwo other air flow openings in the housing. These ERVs are standaloneheat and mass exchangers that are remotely mounted from the heating andcooling system and are not designed to be connected directly to afurnace or an air handler in a heating and cooling system. As connectedto the heating and cooling system, this ERV is costly and cumbersome toinstall as it requires the installation of four separate duct pipes tocarry each air stream to or from the fresh air or stale air spaces.Moreover, these ERVs require low voltage wall controls and an availablepower receptacle, which further complicates the installation process.

Other ERV's are configured to connect directly to a furnace or airhandler blower compartment, eliminating the need for the four ductpipes. These ERV's, however, are prone to allow increased levels ofstale air recirculation in the heating and cooling system.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, an energy recovery systemincludes a heating and cooling system and an energy recovery ventilatoroperably connected to a component of the heating and cooling system. Theenergy recovery ventilator includes a supply port extending into thecomponent to provide a supply of fresh airflow from the energy recoveryventilator to the component of the heating and cooling system for use bythe component. A return port extends into the component configured toreceive a flow of stale air from the component while minimizingingestion of the fresh air flow from the component into the return port.

According to another aspect of the invention, a method of operating anenergy recovery system includes flowing a flow of fresh air from anenergy recovery ventilator through a supply port into a component of aheating and cooling system for use by the component. Stale air is flowedfrom the component through a return port into the energy recoveryventilator. The flow of fresh air is prevented from recirculatingthrough the return port.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a view of an embodiment of an energy recovery ventilator(ERV);

FIG. 2 is a view of another embodiment of an ERV;

FIG. 3 illustrates an embodiment of an ERV connected to a heating andcooling system;

FIG. 4 illustrates embodiments of fresh air and return air ports betweenan embodiment of an ERV and a heating and cooling system;

FIG. 5 illustrates other embodiments of fresh air and return air portsbetween an embodiment of an ERV and a heating and cooling system;

FIG. 6 illustrates still other embodiments of fresh air and return airports between an embodiment of an ERV and a heating and cooling system;

FIG. 7 illustrates yet other embodiments of fresh air and return airports between an embodiment of and ERV and a heating and cooling system;and

FIG. 8 illustrates an alternate view of the embodiments of FIG. 7.

The detailed description explains embodiments of the invention, togetherwith advantages and features, by way of example with reference to thedrawings.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of an energy recovery ventilator (“ERV”) for use with aheating and cooling system includes a generally rectangular housing thatmay be directly attached to an existing furnace/fan coil in the system.The ERV includes a fresh air intake duct and an exhaust air duct. In anembodiment, an outside air stream enters the ERV through the fresh airintake duct while stale conditioned air from an interior conditioned airspace is exhausted through the exhaust air duct. The ERV includes a heatand mass exchange device for recovering energy from the staleconditioned air prior to exhausting the stale conditioned air to anoutside air space. In an embodiment, the ERV may be used with a wallpenetration that provides a simplified duct assembly for connecting theducts to the outside air space. In an embodiment, the ERV may beelectrically wired directly, via a wire line, to a power supply in theheating and cooling system in order to energize the ERV and eliminateproviding a standalone power supply. In one non-limiting embodiment, atwo-wire line may be used to simplify the electrical connection to theheating and cooling system. But, in other embodiments, any number ofwire-lines may be used to electrically connect the ERV to the heatingand cooling system. The ERV may also be connected to a furnace/fan coilcontroller in the heating and cooling system for controlling theoperation of the ERV without requiring an additional dedicatedcontroller for ERV control and operation.

Referring now to the drawings, FIGS. 1-2 illustrate an ERV 2 used inconnection with a heating and cooling system 18 for circulating freshair from the outdoors while recovering energy from stale conditioned airaccording to an embodiment of the invention. Particularly, the ERV 2includes a generally rectangular housing 4 fitted with a fresh airintake duct 6 and an exhaust air duct 10. The fresh air intake duct 6and exhaust air duct 10 are coupled to selectively movable dampers 25,26, respectively. The dampers 25, 26 are selectively controllable by afurnace/fan coil controller (not shown) in response to signals such as,for example, signals indicative of temperature or humidity that arereceived from sensors inside the ERV 2 or inside the interiorconditioned space. In some non-limiting examples, the dampers 25, 26 maybe a valve or plate that stops or regulates the flow of air entering orexiting ERV 2 through the respective ducts 6, 10. The ERV 2 alsoincludes a heat and mass exchange device 14 such as, in somenon-limiting examples, a honeycomb heat exchanger or a brazed-plate heatexchanger for recovering energy from stale conditioned air. The staleconditioned air is received through a return port 20, which is in fluidcommunication with an air return duct coupled to the heating and coolingsystem 18. A fan 16 is coupled to the heat exchange device 14 in orderto induce air movement through the heat exchange device 14 as well asinduce to a positive air pressure in the furnace/fan coil of the heatingand cooling system 18. In an embodiment, as shown with reference to FIG.2, a fan or blower 29 may also be fluidly coupled to the fresh airintake duct to either induce air intake from an outdoor air space 24 orcontrol the air flow rate entering the ERV 2 from the outdoor air space24.

A filter element 27 is coupled to duct connection 6 in order to filterout any dust, debris, pollutants, or the like from the outside airstream 8. Additionally, in an embodiment, a filter element 28 is coupledto a return port 20 to filter an exhaust air stream 12 that is receivedfrom a return air duct that is in fluid communication with an interiorconditioned air space. In another embodiment, a filter element, which issubstantially similar to filter element 28, may be coupled to supplyport 22 near or attached to the face of the heat exchanger 14 in orderto filter the outside air stream 8. In operation, an outside air stream8 from, for example, an outdoor air space 24 enters the ERV 2 throughduct 6 while stale conditioned air from an interior conditioned airspace is received by ERV 2 and exhausted as an exhaust air stream 12through the exhaust air duct 10. Dampers 25, 26 control the air flowrate entering or exiting the ERV 2 or, alternatively, Dampers 25, 26 maybe closed to bypass the ERV 2. The outside air stream 8 circulatesthrough the heat exchange device 14 where energy exchange takes placewithin the heat exchange device 14. The extracted energy is transferredto the outside air stream 8 and it enters the heating and cooling system18 as a fresh air stream through the supply port 22.

In an embodiment, as shown in FIGS. 1-2, the ERV 2 may be electricallywired directly, via a two-wire line, to the heating and cooling system18 in order to energize ERV 2. The direct wiring eliminates need forproviding an additional energizing power supply for energizingelectrical components of the ERV 2. Also, the ERV may be selectively andelectrically coupled to a controller (not shown) located in, forexample, an electronics circuit board of the heating and cooling system18. The controller (not shown) controls operation of the ERV 2 whilealso eliminating a need for an additional controller, therebysimplifying the installation as well as reducing the costs associatedwith installation. In an example, the controller may operate the ERV 2while the furnace/fan coil air circulation blower is on in order toprovide a desired ventilation rate through the heating and coolingsystem 18. In another example, the controller may operate the ERV 2 fora portion of each hour based on the desired ventilation rate and the airflow capacity of the ERV 2. In an embodiment, the controller includes amicroprocessor preprogrammed with software programs that is stored innonvolatile memory for executing algorithms to provide the ERV 2 with avariety of operation modes and control sequences as indicated above.

In another embodiment, shown in FIGS. 1-2, the ERV 2 may be directlyattached to, for example, an air circulation blower compartment of afurnace/fan coil of the heating and cooling system 18 through bolts,screws, or the like. But, in another non-limiting embodiment, the ERV 2may be attached to a return air duct of an air handler without departingfrom the scope of the invention. In an embodiment, the ERV 2 may beelectrically connected to a power supply as well as to a controller ofthe furnace/fan coil, thereby eliminating a need for an additional powerreceptacle or a dedicated controller, respectively. In an embodiment,the heating and cooling system 18 may include fans (e.g., blowers, airhandlers, and the like) to communicate air flow from an interior airspace to the ERV 2. Other system components such as dampers, filters,additional fans, refrigeration and/or heating/dehumidification (e.g.,economizer heat exchangers, heat rejection heat exchangers, and gascoolers/condensers), heat absorption heat exchangers (evaporator) mayalso be provided. In operation, outside air stream 8 enters the housing2 through the duct connection 6 while stale conditioned air from theinterior conditioned air space passes through the heat exchange device14. The heat exchange device 14 extracts energy from the staleconditioned air and exhausts the stale conditioned air as an exhaust airstream 12 from the ERV 2. The outside air stream 8 circulates throughthe heat exchange device 14 where energy is transferred to the outsideair steam 8 within the heat exchange device 14. The outside air stream 8receives the extracted energy and enters the heating and cooling system18 as a fresh air stream through the supply port 22. Further, staleconditioned air 12 is extracted from, in one non-limiting example, areturn air duct that is directly connected to a conditioned air space.The stale conditioned air 12, driven by fan 16, enters the ERV 2 throughreturn port 20, circulates through the heat exchange device 14, andexits the ERV 2 through duct connection 10.

FIG. 3 illustrates an elevation view of an ERV 2 that is in direct airflow communication with a furnace/fan coil 30 of system 18 according toanother embodiment of the invention. As shown, the ERV 2 is sized to bedirectly connected to a circulation air blower compartment 32 offurnace/fan coil 30 and receives an air flow from the compartment 32 forenergy recovery and recirculation to the interior conditioned air space50. The ERV 2 includes a fresh air intake duct 6 and an exhaust air duct10. The ERV 2 also includes a return port 20 and a supply port 22 thatare in direct communication with the circulation air blower compartment32. The ERV 2 is shown installed in a vertical orientation directlycoupled to furnace/fan coil 30, which is also vertically oriented. But,in another embodiment, ERV 2 may be installed in a horizontalorientation in order to be coupled to a corresponding horizontallyoriented heating and cooling system 18 without departing from the scopeof the invention. A stale conditioned air stream 42 from an interiorconditioned air space 50 enters system 18 through the return air duct36. In an embodiment, an air cleaner such as, for example, an airpurifier 38 is provided to filter the stale conditioned air stream 42and communicate a filtered air stream 52 to the negative pressurechamber of circulation air blower compartment 32. In another embodiment,an air filter element (not shown) may be provided in lieu of the airpurifier 38 in order to filter the stale conditioned air stream 42. Thefiltered air stream 52 enters the ERV 2 through return port 20 wherebyenergy is extracted by the heat and mass exchange device 14 (shown inFIGS. 1-2) prior to exiting the ERV 2 to the outdoor air space via duct10. This extracted energy is transferred to an outside air stream 8(shown in FIGS. 1-2) that enters the ERV 2 through intake duct 6. Theoutside air stream 8 (shown in FIGS. 1-2) is further communicated to thecompartment 32 as a fresh air stream 46 through supply port 22. Thefresh air stream 46 mixes with the filtered air stream 52 in thecompartment 32. The circulation air blower 33 creates a positivepressure in a furnace/fan coil compartment 35. The positive pressureovercomes the negative pressure in the circulation air blowercompartment 32 and forces the mixed air from compartment 32 through theevaporator coil compartment 34 for heat-exchange within the evaporatorcoil compartment 34. The mixed air is forced out of evaporator coilcompartment 34 and through the air supply duct 40 as conditionedfiltered air 48 in order to condition the interior conditioned air space50. It is to be appreciated that the ERV 2 mounts directly to thefurnace/fan coil 30 in order to exhaust filtered air stream 52 from airblower compartment 32 while overcoming the negative static pressure inthe blower air compartment 32.

Referring to FIG. 4, an embodiment of a supply port 22 and return port20 is shown. The supply port 22 and the return port 20 extend throughthe ERV housing 4 and into the blower compartment 32, and are secured toone or both of the housing 4 or the blower compartment 32 by, forexample, a snap fit. Alternatively, the supply port 22 and/or the returnport 20 are secured to the housing 4 or the blower compartment 32 byfasteners such as screws, pins or the like. The ports 20 and 22 shown inFIG. 4 have are configured to direct flow in a selected direction andhave, for example, an elbow-shaped cross-section. If the selecteddirection is changed, the flow may be redirected by rotating the ports20 and 22 in openings through which they extend. The ports 20 and 22 arepositioned to reduce recirculation of stale air through the heating andcooling system 18, either through their orientation as above, or throughtheir position in the ERV housing 4, or both. As shown in FIG. 4, thesupply port 22 and the return port 20 are oriented to ensure that thefresh air stream 46 flowing through the supply port 22 into the blowercompartment is directed away from the return port 20 to minimizereingestion of fresh air stream 46 into the return port 20, andmaximizing filtered stale airstream 52 flowed through the return port 20from the blower compartment 32 and into the ERV 2.

In other embodiments, as shown in FIG. 5, the supply port 22 and thereturn port 20 are triangular in cross-section. The triangularcross-section increases the flow path size for the fresh air stream 46and the filtered stale airstream 52 to and from the blower compartment32. Increasing the flowpath size beneficially increases a rate of whichthe fresh air stream 46 can be delivered to the blower compartment 32 aswell as increasing circulation of the filtered stale airstream 52 fromthe blower compartment 32 into the ERV 2 via the return port 20. Asshown in FIG. 6, in some embodiments the return port 20 includes ashield 70 secured to the return port 20. The shield 70 is alsotriangular in shape and includes a shield opening 72 facingsubstantially downward into the blower compartment 32. The shield 70having the downward-facing shield opening 72 reduces recirculation ofthe fresh air stream 46 into the return port 20 by drawing from a lowerperimeter 74 of the blower compartment 32, reducing opportunities forthe fresh air stream 46, which is urged substantially upward by theblower 33.

Referring now to FIG. 7, in some embodiments, the ERV 2 is operablyconnected to a return air duct 36, as an alternative to being connectedto the blower compartment 32. In the embodiment of FIG. 7, a stale airstream 42 is directed through the return air duct 36 toward the ERV 2.At least a portion of the stale airstream 42 is directed into the returnport 20 of the ERV 2 and into the ERV 2, while the fresh airstream 46 isdirected into the return air duct 36 through the supply port 22 towardthe air purifier 38 and the blower compartment 32. The supply port 22and return port 20 are configured and located to prevent reingestion ofthe fresh airstream 46 into the return port 20. As shown in theembodiment of FIG. 7, the return port 20 is located upstream of thesupply port 22 in the return air duct 36. Further, in some embodiments,as shown in FIG. 8, the return port 20 may include a shield 70 with anupstream-facing shield opening 72 to further restrict recirculation ofthe fresh airstream 46 into the return port 20.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A method of operating an energy recovery systemcomprising: flowing a flow of fresh air from an energy recoveryventilator through a supply port into a circulation air blowercompartment of a heating and cooling system for use by the circulationair blower compartment; flowing stale air from the circulation airblower compartment through a return port into the energy recoveryventilator; providing a shield at the return port, the shield having atriangular cross-section in a plane parallel to a side wall of a housingof the energy recovery ventilator in which the report port is disposed;and preventing, via the shield, the flow of fresh air from recirculatingthrough the return port.
 2. The method of claim 1, further comprisingflowing the stale airflow around the shield, the shield configured toprevent reingestion of the flow of fresh air into the return port. 3.The method of claim 1, wherein the return port draws the flow of staleair from a lower perimeter of the circulation air blower compartment.